title: Effect of pill burden on dosing preferences, willingness to pay, and likely adherence among patients with type 2 diabetes.
abstract: OBJECTIVE
  To quantify willingness-to-pay (WTP) for reducing pill burden and dosing frequency among patients with type 2 diabetes mellitus (T2DM), and to examine the effect of dosing frequency and pill burden on likely medication adherence.
  
  
  METHODS
  Participants were US adults with T2DM on oral antihyperglycemic therapy. Each patient completed an online discrete-choice experiment (DCE) with eight choice questions, each including a pair of hypothetical medication profiles. Each profile was defined by reduction in average glucose (AG), daily dosing, chance of mild-to-moderate stomach problems, frequency of hypoglycemia, weight change, incremental risk of congestive heart failure (CHF), and cost. Patients were asked to rate their likely adherence to the profiles presented in each question. Choice questions were based on a predetermined experimental design. Choice data were analyzed using random-parameters logit. Likely treatment adherence was analyzed using a Heckman two-stage model.
  
  
  RESULTS
  Of the 1,114 patients who completed the survey, 90 had lower dosing burden (<5 pills/day taken once/day or as needed) for all medications, and 1,024 had higher dosing burden (≥5 pills/day or more than once/day). Reduction in AG was valued most highly by patients. Hypoglycemia, chance of mild-to-moderate stomach problems, weight change, incremental risk of CHF, and daily dosing were less valued. Patients with higher current dosing burden had lower WTP for more convenient dosing schedules than patients with lower current dosing burden. Changes in dosing and cost impacted likely adherence. The magnitude of the impact of dosing on likely adherence was higher for patients with lower current dosing burden than for patients with higher current dosing burden.
  
  
  CONCLUSIONS
  Patients with T2DM were willing to pay for improvements in efficacy, side effects, and dosing. Patients' WTP for more convenient dosing depended on current dosing burden, as did the effect of these attributes on likely adherence.
authors.affiliation: Health Preference Assessment, Research Triangle Institute (RTI) Health Solutions, Research Triangle Park, NC, USA.
authors.forename: A Brett
authors.initials: AB
authors.lastname: Hauber
authors.forename: Steven
authors.initials: S
authors.lastname: Han
authors.forename: Jui-Chen
authors.initials: JC
authors.lastname: Yang
authors.forename: Ira
authors.initials: I
authors.lastname: Gantz
authors.forename: Kaan
authors.initials: K
authors.lastname: Tunceli
authors.forename: Juan Marcos
authors.initials: JM
authors.lastname: Gonzalez
authors.forename: Kimberly
authors.initials: K
authors.lastname: Brodovicz
authors.forename: Charles M
authors.initials: CM
authors.lastname: Alexander
authors.forename: Michael
authors.initials: M
authors.lastname: Davies
authors.forename: Kristy
authors.initials: K
authors.lastname: Iglay
authors.forename: Qiaoyi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Larry
authors.initials: L
authors.lastname: Radican
keywords: adherence; conjoint analysis; discrete-choice experiment; oral antihyperglycemic therapy; type 2 diabetes mellitus; willingness to pay